• Bulletin of the Korean Chemical Society
• /
• 제35권8호
• /
• pp.2317-2325
• /
• 2014

P-glycoprotein (P-gp) is a member of the ATP-Binding Cassette transporter superfamily and mediates transmembrane efflux of many drugs. Since it is involved in multi-drug resistance activity in various cancer cells, the development of P-gp inhibitor is one of the major concerns in anticancer therapy. Human P-gp protein has at least two "functional" drug binding sites that are called "H" site and "R" site, hence it has multi-binding-specificities. Though the amino acid residues that constitute in drug binding pockets have been proposed by previous experimental evidences, the shapes and the binding poses are not revealed clearly yet. In this study, human P-gp structure was built by homology modeling with available crystal structure of mouse P-gp as a template and docking simulations were performed with inhibitors such as verapamil, hoechst33342, and rhodamine123 to construct the interaction between human P-gp and its inhibitors. The docking simulations were performed 500 times for each inhibitor, and then the interaction frequency of the amino acids at the binding poses was analyzed. With the analysis results, we proposed highly contributing residues that constitute binding pockets of the human P-gp for the inhibitors. Using the highly contributing residues, we proposed the locations and the shapes of verapamil binding site and "R" site, and suggested the possible position of "H" site.

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 1996년도 정기총회 및 학술발표회
• /
• pp.24-24
• /
• 1996

SecA protein of E. coli is essential for the translocation of various precursor proteins across the plasma membrane. Along with it, SecA protein interacts with precursor proteins, SecY/E, SecB and is an ATPase which has multiple ATP binding sites. There is little known about the regulation mechanism of the protein translocation machinery. (omitted)

• 통합자연과학논문집
• /
• 제5권1호
• /
• pp.18-21
• /
• 2012

The resistance of tumour cells against cytotoxic drug is significant limitation in successful chemotherapeutic treatment of cancer. To date, no crystal structure is available for human P-gp. We developed homology model for human P-gp NBD2 by using coordinates of transporter associated protein (TAP1). Docking study was performed for 8-geranyl-chrysin (Flavonoids) inhibitor in the NBD2 model. Ligand-protein interactions were determined which indicates that the 8-geranyl chrysin shares two overlapping sites in the cytosolic domains of P-gp, the ATP site and a hydrophobic steroid-binding site.

• 미생물학회지
• /
• 제41권2호
• /
• pp.93-98
• /
• 2005

Sphingomonas chungbukensis DJ77의 유전체 서열분식 과정에서 969개의 nucleotide로 구성된 sphingosine kinase 유전자를 동정하였다. 이 sphingosine kinase 단백질의 아미노산 서열은 Zymomonas mobilis subsp. mobilis ZM4의 sphingosine kinase 아미노산 서열과 $55\%$의 상동성을 보였다. 또한 다중서열정렬을 통해 각각 진핵세포의 sphingosine kinase의 C2, C3, C5 domain에 속하는 3개의 conserved sequence를 발견하였다. 그 중 하나는 sphingosine kinase에서 ATP-binding site일 것으로 예상되어지는nucleotide-binding motif(GGDG)였고 나머지 둘은 아직 기능이 알려지지 않은 conserved sequences 였다. 이러한 다중서열정렬을 바탕으로 계통수를 그려본 결과, S. chungbukensis DJ77의 sphingosine kinase (SPK)는 COG1597 그룹과 유사했으며, COG1597 내에서 동일종의 diacylglycerol kinase와는 서로 다른 그룹에 속하는 것으로 나타났다. 재조합 SPK는 이종(異種)세포인 Escherichia coli내에서 성공적으로 과발현 되었으나, 세포 내에서 불용성 복합체(inclusion body)를 형성하였다.

• BMB Reports
• /
• 제39권5호
• /
• pp.578-585
• /
• 2006

The cDNA of a firefly luciferase from lantern mRNA of Lampyroidea maculata has been cloned, sequenced and functionally expressed. The cDNA has an open reading frame of 1647 bp and codes for a 548-residue-long polypeptide. Noteworthy, sequence comparison as well as homology modeling showed the highest degree of similarity with H. unmunsana and L. mingrelica luciferases, suggesting a close phylogenetic relationship despite the geographical distance separation. The deduced amino acid sequence of the luciferase gene of firefly L. maculata showed 93% identity to H. unmunsana. Superposition of the three-dimensional model of L. maculata luciferase (generated by homology modeling) and three dimensional structure of Photinus pyralis luciferase revealed that the spatial arrangements of Luciferin and ATP-binding residues are very similar. Putative signature of AMP-binding domain among the various firefly species and Lampyroidea maculata was compared and a striking similarity was found. Different motifs and sites have been identified in Lampyroidea maculata by sequence analysis. Expression and purification of luciferase from Lampyroidea maculata was carried out using Ni-NTA Sepharose. Bioluminescence emission spectrum was similar to Photinus pyralis luciferase.

• Journal of Ginseng Research
• /
• 제10권1호
• /
• pp.55-65
• /
• 1986

GMP를 비롯한 여러가지 누클레오티드들, 긴세노시드 $Rb_2$ 및 산화 환원제들이 쥐의 뇌에서 얻은 입자상 및 가용성 guanylate cyclase의 활동성에 미치는 영향을 조사하였다. GMP, AMP, ADP 및 ATP 들은 낮은 농도에서는 입자상 guanylate cyclase의 활동성에 별로 영향을 미치지 않지만, 그들의 농도가 증가함에 따라서 이 효소들에 대한 억제효과가 증가하였다. 마찬가지로, 가용성 guanylate cyclase의 활동성도 누클레오티드들의 농도가 증가함에 따라서 억제되었다. GMP, AMP, ADP 및 ATP 들의 입자상 guanylate cyclase와 가용성 guanylate cyclase의 활동성에 대한 억제 효과는 긴세노시드 $Rb_2$에 의해서 감소되었다. 이것은 guanylate cyclase분자에 누클레오티드들과 긴세노시드 $Rb_2$에 대한 특이한 결합자리가 있다는 것을 암시하는 것으로 생각된다.$NAD^+$는 입자상 guanylate cyclase의 활동성에 거의 영향을 미치지 않지만, NADH는 이 효소계의 활동성을 억제한다. 입자상 guanylate cyclase는 많이 억제되었다.

• Journal of Microbiology
• /
• 제43권1호
• /
• pp.49-53
• /
• 2005

Putative genes for a two-component signal transduction system (akbS and akbT) were detected near the alkylbenzene-degrading operon of Rhodococcus sp. DK17. Sequence analysis indicates that AkbS possesses potential ATP-binding and histidine autophosphorylation sites in the N- and C-terminal regions, respectively, and that AkbT has a typical response regulator domain. Mutant analysis combined with RT-PCR experiments further shows that AkbS is required to induce the expression of o-xylene dioxygenase in DK17.

• Journal of Microbiology and Biotechnology
• /
• 제13권6호
• /
• pp.949-954
• /
• 2003

The argG gene of Corynebacterium glutamicum encoding argininosuccinate synthetase (EC6345) was cloned and sequenced. The gene was cloned by heterologous complementation of an Escherichia coli arginine auxotrophic mutant (argG/sup -/). The cloned DNA fragment also complements E. coli argD, argF, and argH mutants, suggesting a clustered organization of the genes in the chromosome. The coding region of the argG gene is 1,206 nucleotides long with a deduced molecular weight of about 44 kDa, comparable with the predicted size of the expressed protein on the SDS-PAGE. Computer analysis revealed that the amino acid sequence of the argG gene product had a high similarity to that of Mycobacterium tuberculosis and Streptomyces clavuligerus. Two conserved sequence motifs within the ArgG appear to be ATP-binding sites which correspond to 2 of the 3 conserved regions found in sequences of all known argininosuccinate synthetases.

• 대한의생명과학회지
• /
• 제20권2호
• /
• pp.49-55
• /
• 2014

RalBP1 is an ATP-dependent non-ABC transporter, responsible for the major transport function in many cells including many cancer cell lines, causing efflux of glutathione-electrophile conjugates of both endogenous metabolites and environmental toxins. RalBP1 is expressed in most human tissues, and is over-expressed in non-small cell lung cancer cell lines and in many other tumor types. Blockade of RalBP1 by various approaches has been shown to increase sensitivity to radiation and chemotherapeutic drugs, leading to cell apoptosis. In xenograft tumor models in mice, RalBP1 blockade or depletion results in complete and sustained regression across many cancer cell types including lung cancer cells. In addition to its transport function, RalBP1 has many other cellular and physiological functions, based on its domain structure which includes a unique Ral-binding domain and a RhoGAP catalytic domain, as well as docking sites for multiple signaling proteins. Additionally, RalBP1 is also important for stromal cell function in tumors, as it was recently shown to be required for efficient endothelial cell function and angiogenesis in solid tumors. In this review, we discuss the cellular and physiological functions of RalBP1 in normal and lung cancer cells.

• 한국결정학회:학술대회논문집
• /
• 한국결정학회 2002년도 정기총회 및 추계학술연구발표회
• /
• pp.24-24
• /
• 2002

HtrA (high temperature requirement A), a periplasmic heat shock protein, is known to have molecular chaperone function at low temperatures and proteolytic activity at elevated temperatures. To investigate the mechanism of functional switch to pretense, we have determined the crystal structure of the N-terminal protease domain (PD) of HtrA from Thermotoga maritima. HtrA PD shares the same fold with chymotrypsin-like serine professes. However, crystal structure suggests that HtrA PD is not an active pretense at current state since its active site is not formed properly and blocked by an additional helical lid. On the surface of the lid, HtrA PD has hydrophobic patches that could be potential substrate binding sites for molecular chaperone activity. Present structure suggests that the activation of the proteolytic function of HtrA PD at elevated temperatures might occur by the conformational change.